Nanoelectromechanical resonators for qubit sensing

基于硅自旋的量子比特由于与标准互补金属氧化物半导体（CMOS）工艺的兼容性，在可扩展性方面为量子计算提供了一个有前途的平台。然而，其中一个瓶颈仍然是量子比特的读出，目前的方法依赖于电子读出方法，限制了可扩展性。该项目旨在研究使用纳米机电谐振器作为硅自旋量子比特的读出设备，克服现有方法的潜在限制，提供可扩展的读出平台。纳米机电谐振器以前被用作质量和电荷的高灵敏度转导元件。这些谐振器的典型尺寸在几微米左右，最小间隙和厚度尺寸在几百纳米或更小的范围内。为了研究将这些器件用于量子位读出的可行性，将研究这些器件在低温下的性能，包括能量耗散、自加热和非线性行为。为了在1 μ s或更少的积分时间内实现SNR bb0.1，将追求纳米力学响应的快速读出，并将探索各种电气接口。最初的设备将基于现有的铸造厂制造的原型，建立在研究小组以前的工作基础上。一个特别的重点将是研究NEMS谐振器的非线性行为作为温度的函数，包括在低温下，以期研究利用非线性Duffing响应来提高谐振器侧栅对电荷的灵敏度的可能性。该项目与EPSRC在纳米技术、量子计算、信息和通信技术以及半导体领域的许多战略优先领域保持一致。

Silicon spin-based qubits offer a promising platform for quantum computing in terms of scalability due to their compatibility with standard complementary metal-oxide semiconductor (CMOS) processes. However, one of the bottlenecks remains the readout of the qubits with current approaches relying on electrical readout methods that limit scalability. This project will aim to investigate the use of nanoelectromechanical resonators as readout devices for silicon spin-based qubits overcoming the potential limitations of existing approaches to provide a scalable readout platform. Nanoelectromechanical resonators have previously been employed as highly sensitive transduction elements for mass and charge. These resonators have typical dimensions on the order of a few microns on a side with minimum gap and thickness dimensions in the range of several hundred nanometres or less. To investigate the feasibility of employing these devices for qubit readout, the properties of these devices will be studied at low temperatures including energy dissipation, self-heating, and nonlinear behaviour. Rapid readout of nanomechanical response in order to achieve a SNR>1 in an integration time of 1 us or less will be pursued and a variety of electrical interfaces will be explored. Initial devices will be based on existing foundry-fabricated prototypes building on previous work within the research group. A particular focus will be on studying the nonlinear behaviour of NEMS resonators as a function of temperature including at low temperatures with a view towards investigating the possibility of utilizing nonlinear Duffing response to enhance sensitivity to charge on a resonator side gate.This project aligns with a number of EPSRC strategic priority areas in the fields of nanotechnology, quantum computing, information and communications technology, and semiconductors.